Spatial Dependence of Stimulus Competition in the Avian Nucleus Isthmi Pars Magnocellularis.
Spatial Dependence of Stimulus Competition in the Avian Nucleus Isthmi Pars Magnocellularis.
复制标题
禽类细胞核 Isthmi Pars Magnocellularis 刺激竞争的空间依赖性。
DOI：
10.1159/000500192
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
Mysore,ShreeshP
中科院分区：
文献类型：
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作者：
Schryver,HannahM;Mysore,ShreeshP
峡部大细胞核（Imc）是中脑被盖中的一组特化抑制性神经元，被认为是脊椎动物中保守的。过去在爬行动物中的解剖学研究表明它在刺激选择中的作用，最近在鸟类中的研究也支持了这一点。此外，已知Imc神经元的局灶性失活可消除视顶盖（OT;哺乳动物中的SC）中的所有竞争性相互作用，视顶盖是一个中脑感觉运动中枢，对于控制空间注意力至关重要，从而揭示了Imc在刺激选择中的关键作用。然而，IMC神经元的功能特性还没有得到很好的了解。在这里，与仓鸮Imc的电生理实验，我们表明，Imc神经元本身表现出刺激竞争的签名。空间感受野（RF）外的远距离竞争刺激强烈地抑制了IMC神经元对RF内刺激的反应，并且从所有测试位置沿着仰角和方位角都是如此。值得注意的是，这一点甚至适用于由包含记录位点的大脑的另一侧编码的位置。这种全局分裂抑制独立于竞争刺激的感觉方式而运作。因此，IMC不仅提供抑制OT支持竞争，但本身可能是一个积极的刺激竞争的网站。仓鸮实验的这些结果揭示了脊椎动物中脑选择网络中一个重要节点的功能特性。
The nucleus isthmi pars magnocellularis (Imc) is a group of specialized inhibitory neurons in the midbrain tegmentum, thought to be conserved across vertebrate classes. Past anatomical work in reptiles has suggested a role for it in stimulus selection, which has been supported by recent studies in avians. Additionally, focal inactivation of Imc neurons is known to abolish all competitive interactions in the optic tectum (OT; SC in mammals), a midbrain sensorimotor hub that is critical for the control of spatial attention, thereby revealing a key role for Imc in stimulus selection. However, the functional properties of Imc neurons are not well understood. Here, with electrophysiological experiments in the barn owl Imc, we show that Imc neurons themselves exhibit signatures of stimulus competition. Distant competing stimuli outside the spatial receptive field (RF) suppressed powerfully, and divisively, the responses of Imc neurons to stimuli inside the RF, and did so from all tested locations along the elevation as well as azimuth. Notably, this held true even for locations encoded by the opposite side of the brain from the one containing the recording site. This global divisive inhibition operated independently of the sensory modality of the competing stimulus. Thus, the Imc not only supplies inhibition to the OT to support competition there, but may itself be an active site of stimulus competition. These results from experiments in the barn owl shed light on the functional properties of a vital node in the vertebrate midbrain selection network.